It would be nice if our definition of ‘physical’ incorporated the distinctive content of physics. Attempts at such a definition quickly run into what’s known as Hempel’s dilemma. Briefly: when we talk about ‘physics’, we refer either to current physics or to some idealized version of physics. Current physics is likely wrong and so an unsuitable basis for a definition. ‘Ideal physics’ can’t itself be cashed out except as the science which has completed an accurate survey of the physical; appeals to it to define the physical must therefore end up trivial or circular. So defining the physical in terms of physics looks like a non-starter.